Project Summary/Abstract Dust particles generated during the mining of different types of coal carry different levels of electrostatic charge. To reduce concentrations of airborne respirable dust in underground coal mines, it is critical to find out if surfactants can be chosen to optimize the capture of particles by sprays depending on the sign and magnitude of charge on the dust particles. The long-term goal of this line of research is to reduce respirable dust concentrations in coal mines by improving engineering control technology. The objective of this project is to measure how efficiently sprays containing different types and concentrations of surfactants collect particles carrying various signs and magnitudes of electrostatic charge. To accomplish this objective, a test apparatus will be constructed to measure the ability of sprays to collect airborne particles. This apparatus will be built around an existing wind tunnel and will have separate sections for generating particles, exposing the particles to surfactant sprays, and measuring the efficiency with which particles pass through the spray. The test apparatus will be used to measure the efficiency with which sprays containing different types of surfactants collect standard polystyrene latex (PSL) spheres and coal dust. Several types and concentrations of surfactants will be utilized in water-based sprays. The dust introduced into the wind tunnel will be charged negatively, positively, or in a bipolar manner to allow measurements of the efficiency with which each surfactant can capture particles carrying different signs and levels of electrostatic charge. The data generated in this study will help mine operators make informed decisions about the type of surfactant to use in spray systems to maximize dust capture depending on the characteristics of the coal they are mining.